With the rapid development of electronic technical industries, people use electronic products even more frequently at work and in daily life. When keeping enriching applicable functions of electronic products, appearance designs of the electronic products are also every important that researchers keep modifying and improving. In traditional method of electronic product assemblies, usually assemble a planar glass cover board and a concave rear cover, or dispose a link member between a planar glass cover board and a planar rear cover, and within these two assembled methods, a side surface of an electronic product appears an assembling gap when a electronic-product assembly is completed. Due to the shape differences of electronic-product parts, assembling gaps will appear big or small. If the assembling gaps are at the edge of the viewable area, the user is easily to notice the assembling gaps and the assembling gaps affect the appearance of the electronic product. In addition, to avoid the assembling gaps, the electronic product usually uses a complex assembly art and increase production cost.